/**
 * @file
 * SNMP server MIB API to implement thread synchronization
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Dirk Ziegelmeier <dziegel@gmx.de>
 *
 */

#ifndef LWIP_HDR_APPS_SNMP_THREADSYNC_H
#define LWIP_HDR_APPS_SNMP_THREADSYNC_H

#include "lwip/apps/snmp_opts.h"

#ifdef __cplusplus
extern "C" {
#endif

#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */

#include "lwip/apps/snmp_core.h"
#include "lwip/sys.h"

typedef void (*snmp_threadsync_called_fn)(void *arg);
typedef void (*snmp_threadsync_synchronizer_fn)(snmp_threadsync_called_fn fn,
                                                void *arg);

/** Thread sync runtime data. For internal usage only. */
struct threadsync_data {
    union {
        snmp_err_t err;
        s16_t s16;
    } retval;
    union {
        const u32_t *root_oid;
        void *value;
    } arg1;
    union {
        u8_t root_oid_len;
        u16_t len;
    } arg2;
    const struct snmp_threadsync_node *threadsync_node;
    struct snmp_node_instance proxy_instance;
};

/** Thread sync instance. Needed EXACTLY once for every thread to be synced
 * into. */
struct snmp_threadsync_instance {
    sys_sem_t sem;
    sys_mutex_t sem_usage_mutex;
    snmp_threadsync_synchronizer_fn sync_fn;
    struct threadsync_data data;
};

/** SNMP thread sync proxy leaf node */
struct snmp_threadsync_node {
    /* inherited "base class" members */
    struct snmp_leaf_node node;

    const struct snmp_leaf_node *target;
    struct snmp_threadsync_instance *instance;
};

snmp_err_t snmp_threadsync_get_instance(const u32_t *root_oid,
                                        u8_t root_oid_len,
                                        struct snmp_node_instance *instance);
snmp_err_t
snmp_threadsync_get_next_instance(const u32_t *root_oid, u8_t root_oid_len,
                                  struct snmp_node_instance *instance);

/** Create thread sync proxy node */
#define SNMP_CREATE_THREAD_SYNC_NODE(oid, target_leaf_node,                    \
                                     threadsync_instance)                      \
    {{{SNMP_NODE_THREADSYNC, (oid)},                                           \
      snmp_threadsync_get_instance,                                            \
      snmp_threadsync_get_next_instance},                                      \
     (target_leaf_node),                                                       \
     (threadsync_instance)}

/** Create thread sync instance data */
void snmp_threadsync_init(struct snmp_threadsync_instance *instance,
                          snmp_threadsync_synchronizer_fn sync_fn);

#endif /* LWIP_SNMP */

#ifdef __cplusplus
}
#endif

#endif /* LWIP_HDR_APPS_SNMP_THREADSYNC_H */
